This invention relates generally to tubs and spas, and, more particularly, to a jet for aerating a liquid flow, and the methods by which the jet works.
Hydro-therapy is a useful form of physical therapy. In hydro-therapy, patients rest in a body of water within a spa, while their anatomy is massaged by an aerated water stream flowing out of a hydro-therapy spa jet. The jet provides this stream of aerated water by directing an aerated water stream through a nozzle, into the body of water, and against the portion of the patient's anatomy where the massaging action is desired. A high water stream speed is necessary for aerating the water stream; however, high water stream speeds produce strong aerated water streams that quickly become uncomfortable on many parts of a patient's anatomy. Furthermore, when directional control is incorporated into hydro-therapy spa jets, back pressure generally results, interfering with the process of aeration. Accordingly, it has been an important aim of hydro-therapy spa jet designers to design hydro-therapy spa jets that produce a well-aerated stream of water that is not uncomfortably strong, and may be directionally controlled.
A common form of hydro-therapy spa jet includes a first nozzle that accelerates a stream of water, feeding it into a second nozzle. The accelerated water becomes aerated in the second nozzle, and then passes out through a third nozzle into a body of water with enough penetration to create a massaging action. Proper aeration produces a stream of water that is particularly penetrating. While this design is widely used in the hydro-therapy spa and tub business, it is unforgiving to changes in the first nozzle, air chamber, and third nozzle. Any changes in these areas can cause vast fluctuations in the operation of the jet and can even cause the jet not to draw air, which stops the massaging action.
This design limitation provides a narrow window of parameters in which to operate, and leads to aerated water streams that are strong, and can become relatively uncomfortable after a short time. Efforts to create other hydro-therapy spa jet designs to soften this feel have resulted in jets that perform in a very limited pressure and speed range with very little air being drawn into the water stream.
In an attempt to better regulate the mixture of air and water, some nozzle designs incorporate plugs or rods suspended in the water stream, where the plugs or rods are adjustable to control the size of openings leading either to the air or water supplies. Such plugs or rods naturally extend through the jet's second nozzle to lodge in the pathway of either the air or water sources. These plugs or rods are generally suspended in the water stream by a number of vanes connecting the plug or rod to the third nozzle. Such systems, while providing for adjustable control, do not overcome the above-mentioned problems relating to uncomfortably strong water streams or back pressure. Furthermore, these systems do not feature vanes or protrusions, positioned in an aerated water stream, that have a thickness or cross-sectional area decreasing in the downstream direction.
The use of nozzles with an increasing diameter is known for designs attempting to moderate water stream strength. Such nozzles, however, commonly suffer from significant internal turbulence, leading to additional back pressure. In particular, the portion of the water stream near the nozzle wall decreases in speed more than the water in the center of the nozzle. This speed differential causes turbulence, and thus significant back pressure.
These nozzles also experience a bleed off of the flow around the downstream end of the nozzle. The use of a constant diameter section at the downstream end of an increasing diameter nozzle is known to limit the bleed off problems, accelerating the water stream speed around the water stream's outer edges. The effectiveness of this mechanism, however, is limited by the turbulence already occurring within the nozzle.
It is generally known that a nozzle with a spherical exterior can be mounted in a socket with a conforming spherical interior to produce a directional nozzle that may be rotated in an eyeball-like fashion. Such nozzles, however, deflect only a portion of the water stream, thus disrupting laminar flow and creating a turbulent stream that does not correctly flow to the location at which it is aimed. Furthermore, to the extent that the water is deflected, the deflection causes a turbulence where the nozzle applies turning forces to the water stream, and thus adds to the back pressure that interferes with the aeration process.
Accordingly, there has existed a definite need for a hydro-therapy spa jet to provide directionally controlled aerated water streams at moderate strength. The present invention satisfies these and other needs, and provides further related advantages.